The present invention relates to cross-linked polymer compositions capable of treating body tissues and, more particularly, to aqueous cross-linked polymer solutions and methods of use thereof.
Cross-linked polymer gel materials are widely utilized in the biomedical industry. For example, polysaccharide gels have been applied in contact lenses, blood contact materials, controlled release formulations, wound dressings, bioadhesives, membranes, superabsorbents, cell encapsulation and immunoisolation materials, and tissue engineering scaffolds (Suggs et al., J. Biomater. Sci. Polym. 9: 653-666, 1998; Aebischer et al., Transplantation 58: 1275-1277, 1994; and Atala et al. (J. Urol. 150: 745-747, 1993).
The potential use of polysaccharide gel materials for treating damaged heart tissue has been intensively researched during the past decade.
The main focus of research has been on utilizing polysaccharide gels for treating the heart tissue following myocardial infarction (MI). MI typically causes an acute loss of myocardial tissue and an abrupt increase in loading conditions which induces left ventricular (LV) remodeling. The early phase of LV remodeling involves expansion of the infarct zone, which often results in early ventricular rupture or aneurysm formation. Late remodeling encompasses the entire LV and involves time-dependent dilatation, recruitment of border zone myocardium into the scar, distortion of ventricular shape and mural hypertrophy. Consequently, it may lead to progressive deterioration in contractile function, heart failure and eventually death (Sutton and Sharpe, Circulation 101:2981-2988, 2000; Mann, D. L., Circulation 100:999-1008, 1999; and Jugdutt, B. I., Circulation 108:1395-1403, 2003).
Accordingly, cessation or reversal of progressive chamber remodeling is an important aim of heart failure therapy. Clinical attempts to minimize the devastating effects of MI have thus far failed to effectively repair the irreversible damage inflicted to the heart tissue (Khand et al., Eur. Heart J. 22:153-164, 2001; Jessup and Brozena, S. N. Engl. J. Med. 348:2007-2018, 2003; and Redfield, M. M., N. Engl. J. Med. 347: 1442-1444, 2000).
Recently, attempts to implant living cells in damaged myocardium have given hope for repairing the damaged tissue via promoting tissue regeneration (Etzion et al., J. Mol. Cell Cardiol. 33:1321-1330, 2000; Leor et al., Expert Opin. Biol. Ther. 3:1023-39, 2003; and Beltrami et al., Cell; 114:763-776, 2003). This approach has advanced considerably with the development of 3-D biomaterial scaffolds aimed at supporting implantation of donor cells (e.g., cardiac cells or stem cells) in the myocardium. Lately, 3-D biomaterial scaffolds made of polysaccharide gel were successfully implanted onto damaged myocardium with promising results (Leor et al., Circulation 102:56-61, 2000). However, clinical use of such cell seeded 3-D biomaterial scaffolds is limited due to scarcity of suitable donor cells and the high risk involved in major surgery.
While reducing the present invention to practice, the present inventors generated a stable solution of a cross-linked polymer which can be safely administered into a body tissue, such as a damaged myocardium, using low invasive techniques and which can effectively repair the damaged tissue.